This invention relates generally to structural foundations, and in particular to height-adjustable, structurally suspended slabs for structural foundations.
Structural foundations for residential and light commercial construction are typically designed as either “slab-on-grade” or as “structurally suspended slabs.” Slab-on-grade designs, in which a foundation is constructed and supported directly on the ground, is very cost effective but is also heavily dependent on soil strength and soil stability. Slab-on-grade is also very maintenance intensive and, due to a variety of issues, has historically resulted in a significant amount of litigation. Suspended slabs, on the other hand, are isolated from soil movement and/or problematic soils because they do not sit directly on the ground, but they are very costly relative to slab-on-grade foundations. Suspended slabs involve over-excavating a site and constructing extensive, temporary form work and/or using void boxes to create a void or space between the foundation and the soil. The concrete is poured over the temporary form or void box and allowed to set. This process is labor intensive, adds significantly to construction time and costs, and has no provision for future adjustments of the foundation's height.